Group Behavior: Perhaps the best known -- and feared -- wolf behavior is as a pack. Packs are a sophisticated and often complex social group, essentially a hierarchy (tempting to say pecking order, but that somehow doesn't fit the dignity of a wolf) but a hierarchy that can have a surprising degree of shared responsibility and role playing, especially in the larger packs.

The head of almost every pack is a pair of dominant wolves -- the alpha male and alpha female or alpha pair. This is also referred to as the breeding pair, because as a rule they are the pair in the pack to have pups. Starting with the alpha pair there is a rank order for each wolf in the pack down to the lowest individual, the omega wolf. Relationships in this hierarchy are constantly tested and personality conflicts do occur, sometimes resulting in the dispersal of wolves or even in the killing of individuals.

Pack Life: Wolves don’t always live in packs (think of the legendary lone wolf), but living alone is temporary for most wolves. Packs range in size from 2 (+pups) up to 30 (rare) with an average pack being about 8 individuals. Packs often change size and sometimes disappear, especially when the alpha pair dies. In the Greater Yellowstone Region new packs are formed and old packs disperse every year.

Pack life covers almost every aspect of wolf behavior, but from a survival point of view, hunting and pup-rearing are vital. While an individual wolf can hunt and kill small animals, it’s the packs that are successful in hunting the large ungulates (elk, bison, deer, moose), which are the preferred diet. While individual female wolves (usually the mother) can and do protect and nurture wolf pups, packs also take on the responsibility and are generally more effective. One of the threats to wolf pups are wolves from other packs, in fact, fighting between wolf packs is common and may lead to fatalities. A well known part of wolf behavior, howling, is often associated with territorial positioning -- letting the neighbors know who’s who.

Wolves make a variety of vocalizations: howl, bark, growl, and whimper. Used together with body language, wolves have a sophisticated ability to communicate among themselves -- probably an evolutionary development to further the group (pack) socializing and the ability to hunt as a pack.

Prey: Survival in the harsh climate of Yellowstone requires an innate sense for conservation of energy. Put simply this means expending the least amount of energy to accomplish a task. If a wolf sees two elk, one a robust, rompin’ and stompin’ male, the other a wobble-kneed calf, which is the target? It’s a no-brainer for the wolf as well.

With exceptions, older, sicker, weaker, younger animals are the favored prey. They require less energy to bring down and are usually less dangerous. Wolves do get hurt on the hunt. Tackling big animals with horns like bison and elk is not without risk. Anything but a trivial injury is life-threatening to a wolf, so the risk is great. In Yellowstone, around 85-90 percent of a wolf’s diet comes from elk, with the other portion being filled by prey of opportunity such as deer, moose, and mountain sheep. Antelope would also be prey, but unless sick or very young, antelope can easily outrun a wolf. Wolves also take smaller prey such as rabbits and ground squirrels, especially in summer.

Life and Death: Female wolves conceive once a year during the mating season (from January to April) and can produce a litter from 1 to 14 pups with 4 to 6 being the average. Pups are usually born during the spring in a hole in the ground, a den, and remain there for no more than eight weeks. During this time pups are totally vulnerable and can fall prey to bears, coyotes, and other wolves. Wolves are also subject to disease, such as canine parvo-virus, which is usually hardest on the pups. Wolves reach maturity in 2 to 3 years and in most habitats can live from 6-8 years. There is a relatively high mortality rate, much of it due to the vulnerability of pups to disease. Older wolves die from: Hunting, car accidents, prey-hunting wounds, other wolves, and disease. Very few wolves in the wild die from old age, upwards of 12 to 15 years.

MORE ON WOLVES....
Wolves in Yellowstone: A Short History
Wolf Attacks on People
When and Where to See Wolves
Greater Yellowstone Ecosystem Wolf Pack Map 2008
Issues: How Many Wolves are Enough?